Modular single shot digital radiography for long-length imaging

ABSTRACT

A digital radiographic detector system includes a number of DR detectors enclosed by a housing. A base section with wheels has attached thereto a vertical column with a height adjustable horizontal arm extending therefrom. The housing with DR detectors therein is attached to a distal end of the horizontal arm. The housing comprises a major surface made from a radiolucent material to allow the detectors to capture radiographic images via x-rays transmitted through the major surface of the housing. The housing is configured to support the plurality of DR detectors therewithin.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of, and claims priority to,U.S. patent application Ser. No. 15/815,948, filed Nov. 17, 2017, in thename of Wojcik et al., and entitled TILED DIGITAL RADIOGRAPHY DETECTORSFOR LONG-LENGTH IMAGING, which is a continuation of U.S. patentapplication Ser. No. 14/942,081, filed Nov. 16, 2015, in the name ofWojcik et al., and entitled TILED DIGITAL RADIOGRAPHY DETECTORS FORLONG-LENGTH IMAGING, which claims priority to U.S. Patent ApplicationSer. No. 62/080,454, filed Nov. 17, 2014, in the name of Wojcik et al.,and entitled TILED DIGITAL RADIOGRAPHY DETECTORS FOR LONG-LENGTHIMAGING; this application also claims priority to U.S. PatentApplication Ser. No. 62/769,840, filed Nov. 20, 2018, in the name ofWojcik et al., and entitled SINGLE SHOT DIGITAL RADIOGRAPHY FORLONG-LENGTH IMAGING; this application also claims priority to U.S.Patent Application Ser. No. 62/647,045, filed Mar. 23, 2018, in the nameof Wojcik et al., and entitled MODULAR SINGLE SHOT DIGITAL RADIOGRAPHYFOR LONG-LENGTH IMAGING.

BACKGROUND OF THE INVENTION

The subject matter disclosed herein relates to digital radiography (DR)imaging, in particular, to long-length imaging that requires multiple DRdetectors.

Special cassettes and films of extended length are sometimes used whenimaging a long segment of a subject, such as a human body, with ananalog screen-film technique. An x-ray source and the cassette are bothcentered to the subject to be examined and an x-ray collimator isadjusted to cover the imaging area, whereby a single x-ray exposure isperformed. Flat-panel DR detectors are usually limited to 43 cm inlength. For long-length imaging applications this would require separateexposures to be taken at different regions of the subject. In order tocreate a large, single composite image for diagnosis, the individuallycaptured images of the subject need to be stitched together usingdigital computer-implemented reconstruction techniques.

Two primary approaches are available to acquire long-length imagingexams with flat-panel detectors. In both methods, the detector movesfrom one imaging position to the next behind the subject. In one knownembodiment, the x-ray energy source moves (rotates or tilts) in order totrack and expose the detector. In this x-ray source tilting method, thecentral x-ray pointing direction varies from one exposure position tothe next to deliver the x-rays to the detector. In another knownembodiment, the x-ray source focal spot position is not stationary, buttranslates synchronously with the DR detector parallel to the detector'saxis of travel.

There are advantages to both embodiments. For example, the tilt methodis free of parallax artifacts inherent in the x-ray source translationmethod. Because of parallax distortion, the geometric integrity of thesubject's features in the stitched image may be degraded, particularlyin the stitch overlap regions. Automatic image stitching can be achievedwith high geometric accuracy such as provided by the Carestream DRDirectView Long-Length Imaging System. A high-precision hardware encoderreports the exact detector travel distance between exposures. In adirection transverse to the detector motion axis, software automaticallyanalyzes the subject's features in the overlap regions to find the bestalignment between any two adjacent images. The total stitch error hasbeen demonstrated to be small under stringent exposure conditions.

Automatic exposure control can be used during the long-length imagingexams in order to apply just the right amount of exposure to each regionof the subject for image quality. Software may also automatically adjustexposure discrepancies and compensate for the latitude differences,therefore providing optimized image presentation for each image. Theimage-processing reconstruction algorithm stitches together theindividually optimized, display-presentation-ready images to create asmooth and seamless composite single image for diagnosis. The seam linebetween any two images may be blended without any visible artifactsduring this digital process. Such imaging software should be able toadjust and fine-tune stitch positions to compensate for movement of thesubject during the exam to avoid exposure retakes. In all of theexamples just described, it would be advantageous if multiple DRdetectors could be used to simultaneously capture a compositeradiographic image of a subject in a single exposure.

The discussion above is merely provided for general backgroundinformation and is not intended to be used as an aid in determining thescope of the claimed subject matter.

BRIEF DESCRIPTION OF THE INVENTION

A long length imaging system having a host processor, an x-ray source,and a plurality of radiographic detectors is configured tosimultaneously capture a radiographic image of a portion of a subjectexposed by the x-ray source, and to transmit the partial images to thehost processor whereby the partial images are combined into a longlength image. An advantage that may be realized in the practice of somedisclosed embodiments of multiple DR detector systems is that the imagesare simultaneously exposed and potential movement of the subject duringan imaging exam is eliminated, which results in improved long-lengthimage reconstruction and reduced radiation exposure for a subject.

It is recognized that a significant portion of long length imagingrequires an active imaging area of at least about 17″×33″ and preferablyexpandable to about a 17″×49″ active imaging area. The low attenuationDR detector edge disclosed herein may be used for such embodiments, andadditional configurations described herein are optimized for these sizesof active imaging areas.

Advantages that may be realized in the practice of some disclosedembodiments of the LLI DR detector embodiments disclosed herein includereducing seam artifacts within a LLI area by using a monolithic sensorglass or two tiled sensor panels in a single housing; retainingconnection of DR detector module to a positioning device obviating theneed for a user to lift and position components; utilizing a portablepositioning device to enable erect, supine, and cross table imaging of apatient in an x-ray exam room, or in bedside locations such as theoperating room, emergency room or intensive care unit; and thearrangement can be expanded by utilizing an additional portable DRdetector.

In one embodiment, a digital radiographic detector system includes anumber of DR detectors enclosed by a housing. A base section with wheelshas attached thereto a vertical column with a height adjustablehorizontal arm extending therefrom. The housing with DR detectorstherein is attached to a distal end of the horizontal arm. The housingcomprises a major surface made from a radiolucent material to allow thedetectors to capture radiographic images via x-rays transmitted throughthe major surface of the housing. The housing is configured to supportthe plurality of DR detectors therewithin.

In another embodiment, a digital radiographic detector system includes abase affixed to a floor and a vertical column attached to the base. Amovable support is attached to the vertical column and is movablevertically along the vertical column. A housing is attached to thesupport and has secured therein a plurality of DR detectors each facinga major surface of the housing which is made from a radiolucentmaterial.

In another embodiment, a digital radiographic detector system includes avertical hanger having a plurality of first detent portions (slots)arranged vertically in relation to one another. The vertical hanger isattached to a vertical surface such as a wall. A manually movablesupport is attached to the vertical hanger and is configured to movevertically along the vertical hanger. The movable support has a seconddetent portion to lockably engage any one of the first detent portions.A housing is attached to the movable support, the housing encloses andsupports therewithin a plurality of DR detectors each facing a majorsurface of the housing which is made from a radiolucent material, whichmajor surface faces away from the vertical surface.

This brief description of the invention is intended only to provide abrief overview of subject matter disclosed herein according to one ormore illustrative embodiments, and does not serve as a guide tointerpreting the claims or to define or limit the scope of theinvention, which is defined only by the appended claims. This briefdescription is provided to introduce an illustrative selection ofconcepts in a simplified form that are further described below in thedetailed description. This brief description is not intended to identifykey features or essential features of the claimed subject matter, nor isit intended to be used as an aid in determining the scope of the claimedsubject matter. The claimed subject matter is not limited toimplementations that solve any or all disadvantages noted in thebackground.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the features of the invention can beunderstood, a detailed description of the invention may be had byreference to certain embodiments, some of which are illustrated in theaccompanying drawings. It is to be noted, however, that the drawingsillustrate only certain embodiments of this invention and are thereforenot to be considered limiting of its scope, for the scope of theinvention encompasses other equally effective embodiments. For example,the summary descriptions above are not meant to describe individualseparate embodiments whose elements are not interchangeable. In fact,many of the elements described as related to a particular embodiment canbe used together with, and possibly interchanged with, elements of otherdescribed embodiments. Many changes and modifications may be made withinthe scope of the present invention without departing from the spiritthereof, and the invention includes all such modifications. The drawingsbelow are intended to be drawn neither to any precise scale with respectto relative size, angular relationship, relative position, or timingrelationship, nor to any combinational relationship with respect tointerchangeability, substitution, or representation of a requiredimplementation. In the drawings, like numerals are used to indicate likeparts throughout the various views. Thus, for further understanding ofthe invention, reference can be made to the following detaileddescription, read in connection with the drawings in which:

FIG. 1 is a diagram of an exemplary radiographic imaging system;

FIG. 2 is a schematic diagram of an exemplary imaging array for aradiographic detector;

FIG. 3 shows a perspective view of an exemplary portable wireless DRdetector;

FIG. 4 is a cross-section of a portion of the exemplary portablewireless DR detector of FIG. 3 along section line 4-4;

FIG. 5 is a diagram of an exemplary radiographic imaging systemillustrating positioning of the radiographic energy source and the DRdetector;

FIG. 6 is a cross-section of a portion of an exemplary portable wirelessDR detector according to one embodiment;

FIG. 7 is a cross-section of a portion of an exemplary portable wirelessDR detector according to one embodiment;

FIG. 8 is a cross-section of an exemplary arrangement of multiple DRdetectors in a radiographic imaging system according to one embodiment;

FIG. 9 is a cross-section of an exemplary arrangement of multiple DRdetectors in a radiographic imaging system according to one embodiment;

FIG. 10 is a top view of an exemplary arrangement of multiple DRdetectors in a radiographic imaging system according to the embodimentof FIG. 8;

FIG. 11 is a top view of an exemplary arrangement of multiple DRdetectors in a radiographic imaging system according to the embodimentof FIG. 9;

FIG. 12A is a perspective view of an exemplary imaging systemimplementing an arrangement of DR detectors according to one embodiment;

FIG. 12B is a perspective view of an exemplary imaging systemimplementing an arrangement of DR detectors according to one embodiment;

FIG. 12C is a front view of the exemplary transport apparatus of FIG.12B;

FIG. 13 is a perspective view of an exemplary imaging systemimplementing an arrangement of DR detectors according to one embodiment;

FIGS. 14A-B are front views of an exemplary bucky apparatus according toone embodiment;

FIG. 14C-D are a side view and front view, respectively, of theexemplary bucky apparatus of FIG. 14B as assembled, according to oneembodiment;

FIG. 15 is a perspective view of an exemplary imaging systemimplementing an arrangement of DR detectors according to one embodiment;

FIG. 16 is a flow chart of an exemplary method of operating amulti-detector imaging system;

FIGS. 17A-B are schematic diagrams of exemplary DR LLI assemblies;

FIG. 18 is a functional block diagram of an exemplary DR LLI assembly;

FIG. 19 shows a side view of an exemplary DR LLI mobile system;

FIG. 20 shows a front view of the exemplary DR LLI mobile system of FIG.19;

FIGS. 21A-B illustrates side and front views, respectively, of anotherexemplary DR LLI mobile system;

FIGS. 22A-D illustrate various views of an exemplary DR LLI assembly;

FIGS. 23A-D illustrate various views of another exemplary DR LLIassembly;

FIGS. 24A-F illustrate various positions of an exemplary DR LLI mobilesystem;

FIGS. 25A-B demonstrate a conversion of an exemplary DR LLI mobilesystem;

FIGS. 26A-B illustrate further features of an exemplary DR LLI mobilesystem;

FIGS. 27A-B illustrate further features of an exemplary DR LLI mobilesystem;

FIGS. 28A-B illustrate further features of an exemplary DR LLI mobilesystem;

FIGS. 29A-B illustrate an exemplary floor mounted and wall mounted DRLLI system, respectively; and

FIG. 30 illustrates a supine patient table.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a perspective view of a digital radiographic (DR) imagingsystem 10 that may include a generally curved or planar DR detector 40(shown in a planar embodiment and without a housing for clarity ofdescription), an x-ray source 14 configured to generate radiographicenergy (x-ray radiation), and a digital monitor, or electronic display,26 configured to display images captured by the DR detector 40,according to one embodiment. The DR detector 40 may include a twodimensional array 12 of detector cells 22 (photosensors), arranged inelectronically addressable rows and columns. The DR detector 40 may bepositioned to receive x-rays 16 passing through a subject 20 during aradiographic energy exposure, or radiographic energy pulse, emitted bythe x-ray source 14. As shown in FIG. 1, the radiographic imaging system10 may use an x-ray source 14 that emits collimated x-rays 16, e.g. anx-ray beam, selectively aimed at and passing through a preselectedregion 18 of the subject 20. The x-ray beam 16 may be attenuated byvarying degrees along its plurality of rays according to the internalstructure of the subject 20, which attenuated rays are detected by thearray 12 of photosensitive detector cells 22. The curved or planar DRdetector 40 is positioned, as much as possible, in a perpendicularrelation to a substantially central ray 17 of the plurality of rays 16emitted by the x-ray source 14. In a curved array embodiment, the source14 may be centrally positioned such that a larger percentage, or all, ofthe photosensitive detector cells are positioned perpendicular toincoming x-rays from the centrally positioned source 14. The array 12 ofindividual photosensitive cells (pixels) 22 may be electronicallyaddressed (scanned) by their position according to column and row. Asused herein, the terms “column” and “row” refer to the vertical andhorizontal arrangement of the photosensor cells 22 and, for clarity ofdescription, it will be assumed that the rows extend horizontally andthe columns extend vertically. However, the orientation of the columnsand rows is arbitrary and does not limit the scope of any embodimentsdisclosed herein. Furthermore, the term “subject” may be illustrated asa human patient in the description of FIG. 1, however, a subject of a DRimaging system, as the term is used herein, may be a human, an animal,an inanimate object, or a portion thereof.

In one exemplary embodiment, the rows of photosensitive cells 22 may bescanned one or more at a time by electronic scanning circuit 28 so thatthe exposure data from the array 12 may be transmitted to electronicread-out circuit 30. Each photosensitive cell 22 may independently storea charge proportional to an intensity, or energy level, of theattenuated radiographic radiation, or x-rays, received and absorbed inthe cell. Thus, each photosensitive cell, when read-out, providesinformation defining a pixel of a radiographic image 24, e.g. abrightness level or an amount of energy absorbed by the pixel, that maybe digitally decoded by image processing electronics 34 and transmittedto be displayed by the digital monitor 26 for viewing by a user. Anelectronic bias circuit 32 is electrically connected to thetwo-dimensional detector array 12 to provide a bias voltage to each ofthe photosensitive cells 22.

Each of the bias circuit 32, the scanning circuit 28, and the read-outcircuit 30, may communicate with an acquisition control and imageprocessing unit 34 over a connected cable 33 (wired), or the DR detector40 and the acquisition control and image processing unit 34 may beequipped with a wireless transmitter and receiver to transmitradiographic image data wirelessly 35 to the acquisition control andimage processing unit 34. The acquisition control and image processingunit 34 may include a processor and electronic memory (not shown) tocontrol operations of the DR detector 40 as described herein, includingcontrol of circuits 28, 30, and 32, for example, by use of programmedinstructions, and to store and process image data. The acquisitioncontrol and image processing unit 34 may also be used to controlactivation of the x-ray source 14 during a radiographic exposure,controlling an x-ray tube electric current magnitude, and thus thefluence of x-rays in x-ray beam 16, and/or the x-ray tube voltage, andthus the energy level of the x-rays in x-ray beam 16. The acquisitioncontrol and image processing unit 34 may be referred to herein as a hostsystem or a central processing system. Typically, such a host system maybe configured to control and manage operations of the radiographicimaging system 10 automatically or by providing an operator with variousinput devices to control exposure operations.

A portion or all of the acquisition control and image processing unit 34functions may reside in the detector 40 in an on-board processing system34 a which may include a processor and electronic memory to controloperations of the DR detector 40 as described herein, including controlof circuits 28, 30, and 32, by use of programmed instructions, and tostore and process image data similar to the functions of standaloneacquisition control and image processing system 34. The on-boardprocessing system 34 a may include sufficient electronic memory to storeseveral raw and/or fully processed (e.g., gain, offset, and defectcorrected) DR images. The image processing system may perform imageacquisition and image disposition functions as described herein. Theimage processing system 34 a may control image transmission and imageprocessing and image correction on board the detector 40 based oninstructions or other commands transmitted from the acquisition controland image processing unit 34, and transmit corrected digital image datatherefrom. Alternatively, acquisition control and image processing unit34 may receive raw image data from the detector 40 and process the imagedata and store it, or it may store raw unprocessed image data in localmemory, or in remotely accessible memory.

With regard to a direct detection embodiment of DR detector 40, thephotosensitive cells 22 may each include a sensing element sensitive tox-rays, i.e. it absorbs x-rays and generates an amount of chargecarriers in proportion to a magnitude of the absorbed x-ray energy. Aswitching element may be configured to be selectively activated to readout the charge level of a corresponding x-ray sensing element. Withregard to an indirect detection embodiment of DR detector 40,photosensitive cells 22 may each include a sensing element sensitive tolight rays in the visible spectrum, i.e. it absorbs light rays andgenerates an amount of charge carriers in proportion to a magnitude ofthe absorbed light energy, and a switching element that is selectivelyactivated to read the charge level of the corresponding sensing element.A scintillator, or wavelength converter, may be disposed over the lightsensitive sensing elements to convert incident x-ray radiographic energyto visible light energy. Thus, in the embodiments disclosed herein, itshould be noted that the DR detector 40 (or DR detector 300 in FIG. 3 orDR detector 400 in FIG. 4) may include an indirect or direct type of DRdetector.

Examples of sensing elements used in sensing array 12 include varioustypes of photoelectric conversion devices (e.g., photosensors) such asphotodiodes (P-N or PIN diodes), photo-capacitors (MIS),photo-transistors or photoconductors. Examples of switching elementsused for signal read-out include a-Si TFTs, oxide TFTs, MOS transistors,bipolar transistors and other p-n junction components.

FIG. 2 is a schematic diagram 240 of a portion of a two-dimensionalarray 12 for a DR detector 40. The array of photosensor cells 212, whoseoperation may be consistent with the photosensor array 12 describedabove, may include a number of hydrogenated amorphous silicon (a-Si:H)n-i-p photodiodes 270 and thin film transistors (TFTs) 271 formed asfield effect transistors (FETs) each having gate (G), source (S), anddrain (D) terminals. In embodiments of DR detector 40 disclosed herein,such as a multilayer DR detector (400 of FIG. 4), the two-dimensionalarray of photosensor cells 12 may be formed in a device layer that abutsadjacent layers of the DR detector structure, which adjacent layers mayinclude a rigid glass layer or a flexible polyimide layer or a layercomprising carbon fiber without any adjacent rigid layers. A pluralityof gate driver circuits 228 may be electrically connected to a pluralityof gate lines 283 which control a voltage applied to the gates of TFTs271, a plurality of readout circuits 230 may be electrically connectedto data lines 284, and a plurality of bias lines 285 may be electricallyconnected to a bias line bus or a variable bias reference voltage line232 which controls a voltage applied to the photodiodes 270. Chargeamplifiers 286 may be electrically connected to the data lines 284 toreceive signals therefrom. Outputs from the charge amplifiers 286 may beelectrically connected to a multiplexer 287, such as an analogmultiplexer, then to an analog-to-digital converter (ADC) 288, or theymay be directly connected to the ADC, to stream out the digitalradiographic image data at desired rates. In one embodiment, theschematic diagram of FIG. 2 may represent a portion of a DR detector 40such as an a-Si:H based indirect flat panel, curved panel, or flexiblepanel imager.

Incident x-rays, or x-ray photons, 16 are converted to optical photons,or light rays, by a scintillator, which light rays are subsequentlyconverted to electron-hole pairs, or charges, upon impacting the a-Si:Hn-i-p photodiodes 270. In one embodiment, an exemplary detector cell222, which may be equivalently referred to herein as a pixel, mayinclude a photodiode 270 having its anode electrically connected to abias line 285 and its cathode electrically connected to the drain (D) ofTFT 271. The bias reference voltage line 232 can control a bias voltageof the photodiodes 270 at each of the detector cells 222. The chargecapacity of each of the photodiodes 270 is a function of its biasvoltage and its capacitance. In general, a reverse bias voltage, e.g. anegative voltage, may be applied to the bias lines 285 to create anelectric field (and hence a depletion region) across the pn junction ofeach of the photodiodes 270 to enhance its collection efficiency for thecharges generated by incident light rays. The image signal representedby the array of photosensor cells 212 may be integrated by thephotodiodes while their associated TFTs 271 are held in a non-conducting(off) state, for example, by maintaining the gate lines 283 at anegative voltage via the gate driver circuits 228. The photosensor cellarray 212 may be read out by sequentially switching rows of the TFTs 271to a conducting (on) state by means of the gate driver circuits 228.When a row of the pixels 22 is switched to a conducting state, forexample by applying a positive voltage to the corresponding gate line283, collected charge from the photodiode in those pixels may betransferred along data lines 284 and integrated by the external chargeamplifier circuits 286. The row may then be switched back to anon-conducting state, and the process is repeated for each row until theentire array of photosensor cells 212 has been read out. The integratedsignal outputs are transferred from the external charge amplifiers 286to an analog-to-digital converter (ADC) 288 using a parallel-to-serialconverter, such as multiplexer 287, which together comprise read-outcircuit 230.

This digital image information may be subsequently processed by imageprocessing system 34 to yield a digital image which may then bedigitally stored and immediately displayed on monitor 26, or it may bedisplayed at a later time by accessing the digital electronic memorycontaining the stored image. The flat panel DR detector 40 having animaging array as described with reference to FIG. 2 is capable of bothsingle-shot (e.g., static, radiographic) and continuous (e.g.,fluoroscopic) image acquisition.

FIG. 3 shows a perspective view of an exemplary prior art generallyrectangular, planar, portable wireless DR detector 300 according to anembodiment of DR detector 40 disclosed herein. The DR detector 300 mayinclude a flexible substrate to allow the DR detector to captureradiographic images in a curved orientation. The flexible substrate maybe fabricated in a permanent curved orientation, or it may remainflexible throughout its life to provide an adjustable curvature in twoor three dimensions, as desired. The DR detector 300 may include asimilarly flexible housing portion 314 that surrounds a multilayerstructure comprising a flexible photosensor array portion 22 of the DRdetector 300. The housing portion 314 of the DR detector 300 may includea continuous, rigid or flexible, x-ray opaque material or, as usedsynonymously herein a radio-opaque material, surrounding an interiorvolume of the DR detector 300. The housing portion 314 may include fourflexible edges 318, extending between the top side 321 and the bottomside 322, and arranged substantially orthogonally in relation to the topand bottom sides 321, 322. The bottom side 322 may be continuous withthe four edges and disposed opposite the top side 321 of the DR detector300. The top side 321 comprises a top cover 312 attached to the housingportion 314 which, together with the housing portion 314, substantiallyencloses the multilayer structure in the interior volume of the DRdetector 300. The top cover 312 may be attached to the housing 314 toform a seal therebetween, and be made of a material that passes x-rays16 without significant attenuation thereof, i.e., an x-ray transmissivematerial or, as used synonymously herein, a radiolucent material, suchas a carbon fiber plastic, polymeric, or other plastic based material.

With reference to FIG. 4, there is illustrated in schematic form anexemplary cross-section view along section 4-4 of the exemplaryembodiment of the DR detector 300 (FIG. 3). For spatial referencepurposes, one major surface of the DR detector 400 may be referred to asthe top side 451 and a second major surface may be referred to as thebottom side 452, as used herein. The multilayer structure may bedisposed within the interior volume 450 enclosed by the housing 314 andtop cover 312 and may include a flexible curved or planar scintillatorlayer 404 over a curved or planar the two-dimensional imaging sensorarray 12 shown schematically as the device layer 402. The scintillatorlayer 404 may be directly under (e.g., directly connected to) thesubstantially planar top cover 312, and the imaging array 402 may bedirectly under the scintillator 404. Alternatively, a flexible layer 406may be positioned between the scintillator layer 404 and the top cover312 as part of the multilayer structure to allow adjustable curvature ofthe multilayer structure and/or to provide shock absorption. Theflexible layer 406 may be selected to provide an amount of flexiblesupport for both the top cover 312 and the scintillator 404, and maycomprise a foam rubber type of material. The layers just describedcomprising the multilayer structure each may generally be formed in arectangular shape and defined by edges arranged orthogonally anddisposed in parallel with an interior side of the edges 318 of thehousing 314, as described in reference to FIG. 3.

A substrate layer 420 may be disposed under the imaging array 402, suchas a rigid glass layer, in one embodiment, or a flexible substratecomprising polyimide or carbon fiber upon which the array ofphotosensors 402 may be formed to allow adjustable curvature of thearray, and may comprise another layer of the multilayer structure. Underthe substrate layer 420 a radio-opaque shield layer 418 may be used asan x-ray blocking layer to help prevent scattering of x-rays passingthrough the substrate layer 420 as well as to block x-rays reflectedfrom other surfaces in the interior volume 450. Readout electronics,including the scanning circuit 28, the read-out circuit 30, the biascircuit 32, and processing system 34 a (all of FIG. 1) may be formedadjacent the imaging array 402 or, as shown, may be disposed below framesupport member 416 in the form of integrated circuits (ICs) electricallyconnected to printed circuit boards 424, 425. The imaging array 402 maybe electrically connected to the readout electronics 424 (ICs) over aflexible connector 428 which may comprise a plurality of flexible,sealed conductors known as chip-on-film (COF) connectors.

X-ray flux may pass through the radiolucent top panel cover 312, in thedirection represented by an exemplary x-ray beam 16, and impinge uponscintillator 404 where stimulation by the high-energy x-rays 16, orphotons, causes the scintillator 404 to emit lower energy photons asvisible light rays which are then received in the photosensors ofimaging array 402. The frame support member 416 may connect themultilayer structure to the housing 314 and may further operate as ashock absorber by disposing elastic pads (not shown) between the framesupport beams 422 and the housing 314. Fasteners 410 may be used toattach the top cover 312 to the housing 314 and create a sealtherebetween in the region 430 where they come into contact. In oneembodiment, an external bumper 412 may be attached along the edges 318of the DR detector 400 to provide additional shock-absorption.

FIG. 5 illustrates operation of an embodiment of an imaging system 500which may be used for long-length radiographic imaging of a stationarysubject (not shown) positioned between an x-ray source 501 and DRdetector 400. The x-ray radiation source 501 in the first position 502is aimed at DR detector 400 in position 504 to capture a firstradiographic image of the subject. In the embodiment shown in FIG. 5,the x-ray radiation source may be tilted in the direction indicated byarrow 508 to a second position 512 and aimed at DR detector 400 inposition 506 to capture a second image of the stationary subject,wherein the first and second images each include an image of a differentregion of the same subject. In the embodiment of FIG. 5, a single DRdetector 400 may be moved in the direction indicated by arrow 505 fromthe first position 504 to the second position 506 to capture the twoimages of the subject as just described. In another embodiment, two ormore separate DR detectors 400 may be used, one in each of positions 504and 506, and in positions in between, wherein each DR detector 400 isexposed to one radiographic pulse from the x-ray source 501 firingenergy pulses at positions 502 and 512, and in corresponding positionsin between. In another embodiment, the DR detector 400 may be moved toone or more intermediate positions between positions 504 and 506, withcorresponding intermediate tilt positions of the x-ray source 501between positions 502 and 512 to capture one or more additionalradiographic images. In another embodiment, the x-ray source may beattached to a support at a fixed angle such that the x-ray source 501 isnot tiltable, rather, the support is configured to move vertically andis used to translate the x-ray source 501 to a position corresponding tothe DR detector positions 504 and 506, or to intermediate positions ofthe DR detector 400 as just described. Thus, it should be understoodthat embodiments of imaging system 500 may include various combinationsof one or more DR detectors 400, which may be fixed or moveable,together with an x-ray source 501 that may be tiltable and/or verticallytranslatable. In one embodiment, the one or more positions of DRdetector 400 may overlap, resulting in a plurality of capturedradiographic images that may be stitched together into one long-lengthdigital image of the subject using known computer-implemented imagereconstruction processing techniques.

FIG. 6 illustrates in schematic form another exemplary cross-sectionview along section 4-4 of the exemplary embodiment of the DR detector300 (FIG. 3). Several of the components in the DR detector 600illustrated in FIG. 6 are similar in most respects to the components asdescribed with respect to the DR detector 400 of FIG. 4 and areidentified with the same element numerals. The description of thosecomponents bearing the same element numerals is not repeated here. TheDR detector 600 comprises a housing 614 having a portion made from aradiopaque material extending along a bottom portion of the DR detector600 and also continuously forms at least one edge of the housing 614which, in the perspective of FIG. 6, is located to the left of theinterior volume 450. In separate embodiments, the radiopaque portion ofthe housing 614 may continuously extend long one, two, or three edges ofa DR detector 600 having four edges. If the radiopaque portion of thehousing 614 extends along two edges, it may extend along any twoadjacent and substantially perpendicular edges or along any pair ofopposite substantially parallel edges of the DR detector 600.

In the exemplary embodiment of FIG. 6, a portion of the housing 612 isformed from a radiolucent material. This portion of the housing maycomprise a continuous extension of the top cover 312 (FIG. 4) to form aportion of the housing 612 for the DR detector 600 that is transparentto x-ray radiation. In separate embodiments, the radiolucent portion ofthe housing 612 may continuously extend along one, two, or three edgesof a DR detector 600 having four edges. If the radiolucent portion ofthe housing 612 extends along two edges, it may extend along any twoadjacent substantially perpendicular edges or along any pair of oppositesubstantially parallel edges of the DR detector 600. In order to fastenthe radiolucent portion of the housing 612, a fastener 611, similar inmaterial and shape as fastener 410, may be used in the bottom side ofthe DR detector to sealingly fasten the radiolucent edge of the housing612 to the frame support 416 or to a frame support beam 422. At theedges of the DR detector 600 where the radiopaque housing 614 extendsalong the edges toward the top side 451, the fastener 410 may used asdescribed herein to sealingly fasten it to the radiolucent portion ofthe housing 612. The fastener 611 is positioned in the bottom side 452to minimize or eliminate placement of any DR detector components thatare not radiolucent above, or beyond an edge of, the imaging layer 402closest to a radiolucent edge of the DR detector 600. This helps toprevent artifacts appearing on radiographic images captured usingmultiple overlapping DR detectors 600 as described hereinbelow.Similarly, the integrated circuit readout electronics 424 are positionedproximate a (bottom) side of the sensor array imaging device layer 402that is opposite the x-ray source to minimize or eliminate placement ofany electronic components that are not radiolucent above, or beyond anedge of, the imaging device layer 402 closest to a radiolucent edge ofthe DR detector 600.

FIG. 7 illustrates in schematic form another exemplary cross-sectionview along section 4-4 of the exemplary embodiment of the DR detector300 (FIG. 3). Several of the components in the DR detector 700illustrated in FIG. 7, such as the multilayer structure, are similar inmost respects to the components as described with respect to the DRdetector 400 of FIG. 4 and are identified with the same elementnumerals. The description of those components bearing the same elementnumerals is not repeated here. The DR detector 700 comprises a housinghaving a portion made from a radiopaque material 714 extending along abottom portion of the DR detector 700 and may continuously form one ortwo edges of the housing 714 wherein, in the perspective of FIG. 7, onesuch edge may be located behind the multilayer structure as depictedtherein. In separate embodiments, the radiopaque portion of the housing714 may continuously extend long one or two edges of the housing 712 ofthe DR detector 700 having four edges. If the radiopaque portion of thehousing 714 extends along two edges, it may extend along opposite edgesof the DR detector 700.

In the exemplary embodiment of FIG. 7, a portion of the housing 712 isformed from a radiolucent material. This portion of the housing maycomprise a continuous extension of the top cover 312 (FIG. 4) to formopposite edges of the housing 712 for the DR detector 700 that aretransparent to x-ray radiation. In separate embodiments, the radiolucentportion of the housing 712 may continuously extend along two, three, orall edges of a DR detector 700 having four edges. In the perspective ofFIG. 7, two opposite edges (left and right) are formed from aradiolucent material, such as a carbon fiber reinforced plastic,polymeric, or other plastic based material. The housing 712 may extendvertically between the top side and the bottom side, or it may extend ata non-orthogonal angle therebetween, as shown in FIG. 7. In order tofasten the radiolucent portion of the housing 712, fasteners 711,similar in material and shape as fastener 410, may be used in the bottomside of the DR detector to sealingly fasten the radiolucent edge of thehousing 712 to the frame support 416, or to the frame support beam 422,as shown. The fasteners 711, as well as integrated circuit readoutelectronics 424 are positioned proximate the bottom side 452, which is aside of the sensor array imaging device layer 402 that is opposite thex-ray source to minimize or eliminate placement of any DR detectorcomponents that are not radiolucent above, or beyond an edge of, theimaging layer 402 closest to a radiolucent edge of the DR detector 600.This helps to prevent artifacts appearing on radiographic imagescaptured using multiple overlapping DR detectors 700 as describedhereinbelow.

As described herein, DR detector embodiments 400, 600, and 700 areusable individually, as in standard diagnostic radiographic imagingpractice, and may be combined, or tiled, as described herein, forlong-length imaging. FIG. 8 illustrates a side view of an exemplaryarrangement of three DR detectors including two standard DR detectors400, and a central DR detector 700, as describe herein with reference toFIG. 7, having at least two opposite edges of its housing formed fromradiolucent material that each overlap one edge of one of the standardDR detectors 400, as shown. The central DR detector 700 is positionedforward of the standard DR detectors 400 in relation to an x-ray energysource positioned to emit x-rays in a direction as depicted in FIG. 4and FIG. 7. The central DR detector includes an imaging array layerhaving one of its edges 705 overlapping an edge of the imaging arraylayer 307, in a corresponding first one of the standard DR detectors400, by a distance 820, and an opposite edge of the imaging array layer707 overlapping an edge of the imaging array 305, in a correspondingsecond one of the standard DR detectors 400, by a distance 821. Theoverlapping distances 820, 821 may be equivalent or different. Theoverlap distance is not critical to the presently disclosed invention,and may range from one or more millimeters to tens or hundreds ofmillimeters. Because the edges of the DR detector 700 that overlap theedges of the standard DR detectors 400 are radiolucent, and haveeliminated or minimized components, such as electronic readout circuits,beyond the edges of the imaging layer 402 therein, a radiographic imagecaptured simultaneously by the three detectors as depicted in FIG. 8,will not include unnecessary artifacts in the portions of theradiographic image captured by the standard DR detectors 400 caused byradiopaque components in the central DR detector 700 that otherwisewould be disposed therein beyond the overlapping region if DR detector700 was configured as a standard DR detector. One advantage of theembodiment depicted in FIG. 8 is that the two prior art standarddetectors 400 may be used to capture a long-length image when combinedas shown with only one new modified DR detector 700. The embodimentillustrated in FIG. 8 does not require obtaining several DR detectorswith modified radiolucent edges. Thus, a radiographic imagesimultaneously captured by the three DR detectors arranged as in FIG. 8,may be accurately stitched together, without having to mask or processunnecessary artifacts, using standard computer implemented digitalreconstruction techniques. Such known digital reconstruction methodsinclude techniques for correcting geometric alignment of images from DRdetectors having different source-to-image distance. In the exampleembodiment shown in FIG. 8, a source-to-image distance of the DRdetector 700 may be less than that of the DR detectors 400.

FIG. 9 illustrates a side view of an exemplary arrangement of DRdetectors including one standard central DR detector 400, and two DRdetectors 600, as described herein with reference to FIG. 6, each havingone edge of its housing formed from radiolucent material that overlapsone edge of the standard central DR detector 400, as shown. The centralstandard DR detector 400 is positioned rearward of the DR detectors 600in relation to an x-ray energy source positioned to emit x-rays in adirection as depicted in FIG. 4 and FIG. 6. The central standard DRdetector 400 includes an imaging array layer having one of its edges 313overlapped by an edge of the imaging array layer 607 in a correspondingfirst one of the DR detectors 600 by a distance 822, and an oppositeedge of the imaging array layer 311 overlapped by an edge of the imagingarray layer 605 by a distance 823 in a corresponding second one of theDR detectors 600. The overlapping distances 822, 823 may be equivalentor different. The overlap distance is not critical to the presentlydisclosed invention, and may range from one or more millimeters to tensor hundreds of millimeters. Because the respective edge of each of theDR detectors 600 that overlaps the edge of the standard DR detector 400is radiolucent, and has eliminated or minimized radiopaque components,such as integrated electronic read out circuits, beyond the edge of theimaging layer therein, a radiographic image captured simultaneously bythe three detectors as depicted in FIG. 9, will not include unnecessaryartifacts in the portion of the radiographic image as captured by thestandard DR detector 400 caused by radiopaque components in the DRdetectors 600 that otherwise would be disposed therein beyond theoverlapping region if DR detectors 600 were configured as standard DRdetectors. One advantage of the embodiment depicted in FIG. 9 is that aprior art standard detector 400 may be used to capture a long-lengthimage when combined as shown with two new modified DR detectors 600 eachhaving only one edge modified to be radiolucent. The embodimentillustrated in FIG. 8 does not require obtaining several DR detectorswith modified radiolucent edges. Thus, a radiographic imagesimultaneously captured by the three DR detectors arranged as in FIG. 9,may be accurately stitched together without having to mask or processunnecessary artifacts using standard computer implemented digitalreconstruction techniques. Such known digital reconstruction methodsinclude techniques for correcting geometric alignment of images from DRdetectors having different source-to-image distance. In the exampleembodiment shown in FIG. 9, a source-to-image distance of the DRdetectors 600 may be less than that of the DR detector 400.

FIGS. 10 and 11 illustrate front or top views of the DR detectorarrangements as depicted in FIGS. 8 and 9, respectively. As shown, twostandard DR detectors 400 are positioned rearward of the DR detector 700in FIG. 10, in relation to an x-ray source that, in the perspective ofFIG. 10, emits x-ray energy toward the page. The DR detector 700,positioned in front, and in the middle, of the two standard DR detectors400, includes radiolucent edges at its top and bottom edges in theFigure, which overlap the edges of the DR detectors 400, as described inrelation to FIG. 8. In FIG. 11, two DR detectors 600, each as describedand configured as in the description of FIG. 6, are positioned in frontof the standard DR detector 400 in FIG. 11, in relation to an x-raysource that, in the perspective of FIG. 11, emits x-ray energy towardthe page. The DR detectors 600 each include at least one radiolucentedge (at least the top or bottom edge) which overlaps a correspondingedge of the middle-positioned standard DR detector 400, as described inrelation to FIG. 9. While particular arrangements of DR detectors havebeen illustrated in FIGS. 8-11, it should be noted that those skilled inthe art may envisage that various combinations of DR detectors may beimplemented in various geometric combinations. Thus, different types ofDR detectors may be utilized in upper, middle, or lower positions, ormay be used in combination with four or more detectors, having edgesoverlapping, wherein each of the DR detectors may be configured toinclude one, two, three, or four radiolucent edges. Such combinationsare considered to be within the scope of the present invention so longas any radiolucent edge of a DR detector is positioned to overlap animaging array of another DR detector. Radiopaque edges may be positionedrearward of another overlapping DR detector, or may be positioned on anexterior border of the arrangement of DR detectors. Alternatively, someor all of the tiled DR detectors may be arranged in a staggered stepwisefashion (FIG. 13), rather than having one central DR detector positionedforward or rearward of the other detectors.

FIG. 12A illustrates a DR imaging system 1200 using the arrangement ofDR detectors as described in relation to FIG. 9 and FIG. 11 for use in along-length imaging exposure. DR detector 1201 may comprise a wired orwireless DR detector of the type 600 described in relation to FIG. 6; DRdetector 1202 may comprise a wired or wireless standard DR detector typeof the type 400 described in relation to FIG. 4; and DR detector 1203may comprise another wired or wireless DR detector of the type 600.X-ray source 501 may be fired once to expose a subject (not shown) to anx-ray beam 16 when the subject is placed between the x-ray radiationsource 501 and the multiple DR detectors 1201-1203, to capture adistributed image of the subject that is simultaneously captured andstored by the multiple DR detectors 1201-1203. The captured images, eachcomprising a portion of the subject, one from each DR detector, may bestitched together using known computer implemented reconstructiontechniques to generate a single long-length composite image of thesubject. Part of the control operations carried out by the imageprocessing and control unit 34 may include wired or wirelesscommunication with the DR detectors 1201-1203 for verification that theDR detectors have been initiated and are all in a ready state beforeexposure, for synchronization, and for coordinating storage andidentification of image frame data from each of the detectors. Such amethod does not require time consuming repositioning of DR detectors1201-1203, repositioning of the x-ray source 501, or multiple exposures,as may be currently practiced to obtain a long-length radiographicimage. The arrangement of DR detectors 1201-1203 may be configured byattachment to a rigid, rollable floor stand structure 1200 using amodified “bucky” arrangement to fix in position each of the DR detectors1201-1203, or the detectors 1201-1203 may be affixed to a wall mountedstructure 1200. Alternatively, the DR detector 1202 may be part of anexisting permanent radiographic imaging installation which is fixed in arelative position as shown, while the other two DR detectors 1201, 1203,may be portable DR detectors installed into the mounting structure to betemporarily used for long-length imaging. One embodiment of the presentinvention may comprise a retrofittable separate structure fortemporarily securing in position the DR detectors 1201 and 1203 as shownand allowing movement of the structure having these two detectors 1201,1203, to position them in front of (overlapping) the fixed installationof DR detector 1202, as will be described below in relation to FIG. 12B.Although the arrangement of DR detectors 1201-1203 has been illustratedas a vertically adjacent alignment wherein the imaging planes of the DRdetectors are also vertical, it should be noted that any of the tiledarrangements of DR detectors disclosed herein may be positioned adjacentto each other in a substantially horizontal alignment wherein theimaging planes of the DR detectors are horizontal, such as may be usedfor a human patient who is lying down on an examination bed with anx-ray source positioned above the patient for full length body imaging,or the DR detectors disclosed herein may be placed adjacent to eachother horizontally wherein the imaging planes of the DR detectors arevertical.

FIG. 12B illustrates a DR imaging system 1250 using an arrangement of DRdetectors as described in relation to FIG. 12A for use in a long-lengthimaging exposure, except that the DR detectors 1201, 1203 are affixed toa transport apparatus 1251 comprising a support post 1254 attached to abase 1256 outfitted with means for transporting the apparatus 1251 andDR detectors 1201, 1203, such as wheels 1257 which may include freelyrotatable wheels, lockable wheels, wheels that may be lowered or raisedby hand cranking or by electric motor under operator control, wheelsthat are not motor-assisted, and motor driven wheels that may be poweredby an electric motor to assist in manually transporting the apparatus1251 by rolling it over a floor or other surface. The support post 1254secures in a vertical relative position the DR detectors 1201, 1203,using one or more cross-beams attached to the support post 1254, with apreselected gap size therebetween 1255 sufficient for the respectivebottom and top edges of the DR detectors 1201, 1203, to overlap a topand bottom edge of DR detector 1202, as previously described. Asmentioned above, the DR detector 1202 may represent a standard prior artDR detector permanently installed on one wall 1252 such as in a medicalfacility imaging room. The DR detector 1202 may be used alone with x-raysource 501 for standard non-elongated radiographic imaging and, in thecase where a long-length radiographic image may be desired, theapparatus 1251 may be rolled into position 1260 along a floor of animaging room. Similarly, DR detectors 1201, 1203, may be portable, to beused individually for performing standard radiographic imaging ofpatients and may be inserted or attached to support post 1254 toconfigure the transport apparatus 1251 as described herein. Thus, theportable pair of DR detectors 1201, 1203, may be advantageously affixedto the transport apparatus 1251 to provide a capability to easilyconvert the permanent installation of the standard DR detector 1202 intothe long-length imaging system 1250 when combined as shown with two newmodified DR detectors of the type 600 each having one or more edgesbeing radiolucent.

As before, x-ray source 501 may be fired once to expose a subject (notshown) when the subject is placed in front of the multiple DR detectors1201-1203. Part of the control operations carried out by the imageprocessing and control unit 34 may include wired or wirelesscommunications, wherein wireless communications are represented aswireless transmission signals 1258, with the DR detectors 1201-1203,such as waiting for and synchronizing ready state signals from allactivated DR detectors 1201-1203 before an exposure by x-ray source 501.Such a method does not require time consuming repositioning of one ormore DR detectors 1201-1203, repositioning of the x-ray source 501, ormultiple exposures, as may be currently practiced to obtain along-length radiographic image.

FIG. 12C illustrates a front view of the transport apparatus 1251 of theDR imaging system 1250 of FIG. 12B. Stationary registration markers1261, 1262, which may be rigidly affixed to support frame 1254, may beused to assist in properly aligning a radiographic image of a subjectpartially captured by each of two or more detectors 1201-1203. Precisionalignment assists in digitally stitching together the capturedradiographic images to form an accurate long length radiographic imageof the subject. The registration markers 1261, 1262, may be made from aradiopaque material such that a portion of the registration markers1261, 1262 appear in calibration images captured by the DR detectors1201-1203. In one embodiment, two partial radiographic images of asubject captured simultaneously by the DR detectors 1201 and 1202 may beprecisely aligned using a location of the registration marker 1261 whichappears at a particular row of the photosensor array in both calibrationimages. In another embodiment, two partial radiographic images of asubject captured simultaneously by the DR detectors 1202 and 1203 may beprecisely aligned using a location the registration marker 1262 whichappears at a particular row of the photosensor array in both calibrationimages. In another embodiment, three partial radiographic images of asubject captured simultaneously by the DR detectors 1201-1203 may beprecisely aligned using locations of the registration markers 1261,1262, which appear at particular rows of the photosensor arrays in allthree calibration images. The row location (e.g. array row number) ofthe marker 1261 as it appears in the calibration image captured by thedetector 1201 may be aligned, for digital stitching purposes, with therow location (e.g. array row number) of the marker 1261 as it appears inthe calibration image captured by the detector 1202. Similarly, the rowlocation (e.g. array row number) of the marker 1262 as it appears in thecalibration image captured by the detector 1203 may be aligned, fordigital stitching purposes, with the row location (e.g. array rownumber) of the marker 1262 as it appears in the calibration imagecaptured by the detector 1202, thereby allowing the three partialradiographic images of a subject captured simultaneously by detectors1201-1203 to be precisely aligned and stitched together to form a longlength image of the subject.

In an example method embodiment, the detector 1201 may be detached fromits cross-beam support and the detector 1202 flashed (exposed without asubject to be imaged) by the source 501 (FIG. 12B) to capture a preciseposition of the marker 1261 as it appears in such a captured calibrationimage frame of detector 1202, such as by identifying a precise row, orrows, of the two dimensional array of photosensors where the marker 1261appears. Thereafter, the detector 1201 may be reattached to itscross-beam support and similarly flashed by the source 501 to capture aprecise position of the marker 1261 as it appears in the capturedcalibration image frame of detector 1201, such as by identifying aprecise row, or rows (depending on photosensor resolution), of the twodimensional array of photosensors where the marker 1261 appears. Suchflash exposures may also be used to capture a correction image, orcorrection map, of the detector's photosensor array such as a gaincorrection map to be used for final image correction, as describedhereinbelow.

A subject to be radiographically imaged may be positioned between thedetectors 1201, 1202 and the x-ray source 501, and exposed by the source501 whereby radiographic images of the subject are captured by detectors1201 and 1202. The radiographic exposure and image capture of thesubject may take place before or after the calibration images arecaptured. The markers 1261-1263 may be configured to be removable ornot, and may be removed prior to radiographic imaging of the subject, ifdesired. The captured radiographic images of the subject can then bedigitally stitched together to form a long length image, using wellknown techniques, relying upon the precise overlap position of themarker 1261 in each corresponding photosensor row of the images asdetermined by the captured calibration images. The identified row in theradiographic image captured by detector 1201 may be overlapped preciselyon the identified row of the radiographic image captured by the detector1202 to determine an exact overlap alignment of the images. In a similarprocess, a long length radiographic image of a subject may be formedusing the detectors 1202 and 1203 and marker 1262. Similarly, all threedetectors 1201-1203 and the both markers 1261-1262, may be used tocapture calibration images, whereby a three detector exposure and imagecapture of a subject may be used to form an even longer lengthradiographic image comprising radiographic images from all threedetectors digitally stitched together. In an example method using threedetectors 1201-1203, the detector 1202 may be flashed with both markers1261 and 1262 captured in its calibration frame (while detectors 1201,1203 are removed from the support frame 1254) to determine in which rowsthe markers 1261 and 1262 appear, and thereafter each detector 1201 and1203 may be replaced onto the support frame 1254 and flashed to formtheir calibration images and to determine the row location of marker1261 in the calibration image of detector 1201, and the row location ofmarker 1262 in the calibration image of detector 1203. The threecaptured radiographic images of the subject can then be digitallystitched together to form a long length image, using well knowntechniques, relying upon the identified overlap row locations of themarkers 1261 and 1262 in each corresponding photosensor row of theoverlapping images, as described above.

In another embodiment, radiopaque markers 1261, 1262, may be rigidlyaffixed to support frame 1254 at precisely the top and bottom rowlocations of the photosensor array of detector 1202. In this embodiment,calibration images may not be required to determine a row position ofany of the markers 1261, 1262 in the calibration images. The markers1261, 1262 may each be positioned such that it appears proximate an edgeof a captured radiographic image of a subject. Because the markers 1261,1262, are radiopaque they may appear in the radiographic images of thesubject as white areas or points in the image. As shown in FIG. 12C, atip of marker 1261 would appear proximate an edge of a radiographicimage of a subject captured by detector 1201 and a tip of marker 1262would appear proximate an edge of a radiographic image of a subjectcaptured by detector 1203. Because the precise location of the markers1261, 1262, appearing in the subject radiographic images are known to bealigned with the top and bottom rows of the photosensor array ofdetector 1202, a precise row overlap of the captured radiographic imagesof the subject as between the detector 1202 and either or both of thesubject radiographic images captured by detectors 1201 and 1203 can beobtained to digitally stitch together a long length image of thesubject. As detailed in the methods disclosed above, any two adjacentdetectors, or all three detectors, may be used to capture a long lengthradiographic image of the subject.

In another embodiment, a radiopaque marker 1263 may be rigidly affixedto support frame 1254 in a similar manner as radiopaque markers1261-1262. The markers 1261-1263 may be affixed to support frame 1254 atprecisely known distances from each other. In this embodiment,calibration images may not be required to determine a row position ofany of the markers 1261-1263 in the calibration images. The markers1261-1263 may each be positioned such that it appears proximate an edgeof a captured partial radiographic image of a subject. As shown in FIG.12C, marker 1261 would appear proximate an edge of a radiographic imageof a subject partially captured by detector 1201. Similarly, marker 1262would appear proximate an edge of a partial radiographic image of asubject captured by detector 1203, and marker 1263 would appearproximate an edge of a partial radiographic image of a subject capturedby detector 1202. Because the precise distance between the markers1261-1263 are known, any of the markers 1261-1263 appearing in thepartial radiographic images of the subject may be used to preciselyoverlap the images by a known amount and digitally stitch together thepartial captured radiographic images to form a complete long lengthimage. Although the sizes of the markers 1261-1263 in FIG. 12C may beexaggerated, as illustrated, for clarity, their sizes may vary. In oneembodiment, the marker may be a small rod, or it may be as small as afine wire or needle. The marker may be permanently affixed to thedetector or to the support structure that secures the detector in place,or it may be insertable through an opening in a side wall of thedetector such as by snapping it into place or threading it through ascrew hole, for example. As described in the methods above, any twoadjacent detectors, or all three detectors, may be used to capture along length radiographic image of a subject.

In one embodiment, the detectors 1201-1203 may be secured in positionfor radiographic imaging of a subject and flashed by the x-ray source501 to capture an offset calibration image whereby the overlappingdetector's attenuation of x-rays impacting a portion of the overlappedphotosensor array is captured by the overlapped detector. Such acalibration image may be referred to as an overlap gain map, or overlapgain correction image.

Other correction images may also be captured and stored by the detectors1201-1203 as correction maps for the photosensor array, such as gainmaps or offset maps, which are then combined with captured radiographicimages during image finalization to correct for deviations in individualimaging pixels of the photosensor array. As described above, the markers1261-1263 may be also be used to align one or more correction mapscaptured by the detectors 1261-1263. The apparatus and methods ofoperating the radiographic imaging systems described herein with respectto obtaining and using correction maps are described in more detailhereinbelow.

FIG. 13 illustrates an embodiment of a DR imaging system 1300 whereinmore than three DR detectors are positioned in an overlapping fashion tocapture a long-length radiographic image. X-ray source 501 may emit asingle radiographic energy pulse that is received and captured by DRdetectors 1301-1305 as shown. A subject positioned in front of the DRdetectors 1301-1305 may result in radiographic images being generated inthe DR detectors 1301-1305, each comprising a portion of a radiographicimage of the subject using the single radiographic energy pulse. Asshown, DR detector 1301, the uppermost DR detector as shown, isillustrated as a DR detector 600 as described herein with reference toFIG. 6. Because DR detector 1301 is not positioned forward of another DRdetector, it may alternatively comprise a standard DR detector such asthe DR detector 400 described in relation to FIG. 4. Moreover, DRdetector 1301 may comprise a DR detector such as the DR detector 700described in relation to FIG. 7. Such alternate configurations areconsidered to be encompassed by the present disclosure because theyembody preferred configurations wherein a radiopaque edge of any DRdetector used does not overlap the imaging array of another DR detectorpositioned behind it. In similar fashion, DR detector 1302, second fromthe top as shown, may comprise a detector of the type described inrelation to FIG. 7 wherein opposite edges (top and bottom edges in theperspective of FIG. 13) are configured to be radiolucent; DR detector1303, third from the top as shown, may comprise a standard DR detector400 of the type described in relation to FIG. 4, or it may comprises aDR detector 600 or 700 as described in relation to FIG. 6 and FIG. 7,respectively; DR detector 1304, fourth from the top as shown, maycomprise a DR detector 600 as described in relation to FIG. 6 whereinonly its upper edge is configured to be radiolucent; and DR detector1305, at the bottom of the arrangement as shown, may similarly comprisea DR detector 600 as described in relation to FIG. 6 wherein only itsupper edge is configured to be radiolucent. The detectors 1303-1305 arepositioned in a staggered stepwise arrangement, which stepwisearrangement may comprise an alternative arrangement for all the DRdetectors 1301-1305, as desired. As shown, the DR detectors 1301-1305may be fixed to a support structure 1300 for securing in position the DRdetectors 1301-1305.

FIG. 14A-14D illustrate a bucky apparatus 1400 that includes aretractable frame to allow positioning of two or more DR detectorsadjacent to each other for radiographic image capture. As shown in FIG.14A, bucky apparatus 1400 may be attached to a wall, to a transportapparatus 1251 (FIG. 12C), or the bucky apparatus 1400 may be attachedto a bed in a horizontal orientation. The bucky base 1407 may alsoinclude attachment portions 1410 (FIG. 14C) to assist in securing thebucky apparatus to a wall or to the cross-beams of transport apparatus1251. The bucky apparatus 1400 may used to support a single DR detector1402 in an imaging orientation, such as shown in FIG. 14A, using framemembers 1405 and 1406, during radiographic imaging of a subject. Theframe members 1405-1406 may be slidably connected to a bucky base 1407that allows frame members 1405-1406 to be both or individually movedapart, in the directions shown by the arrows in FIG. 14A, while thebucky base 1407 secures detector 1402 in place, as shown in FIG. 14B.Upon separating one or both of the frame members 1405, 1406, one or bothof additional detectors 1401, 1403, may be inserted into one or both theframe members 1405, 1406, respectively, in the directions shown by thearrows in FIG. 14B, so that the one or both inserted detectors 1401,1403, are secured in a vertically adjacent position with respect to thedetector 1402. It should be understood that the bucky apparatus 1400 maybe configured to allow, in one embodiment, the additional one or bothdetectors 1401, 1403, to be secured in position in front of the detector1402 and, in another embodiment, to be secured in position behind thedetector 1402 as shown in FIG. 14B. In either embodiment, appropriatedetector constructions as exemplified and described in relation to FIGS.8-9 herein may be selected. It should also be understood that the buckyapparatus 1400 may be configured with markers similar to markers1261-1263 as described in relation to FIG. 12C. Thereby, in an exemplarythree-detector embodiment, the fully assembled bucky apparatus 1400, asshown in the side view of FIG. 14C and the front view of FIG. 14D, maybe used for long length imaging in combination with the methods andconfigurations described herein.

FIG. 15 illustrates a method of capturing radiographic images of asubject to be used in generating tomosynthesis images of a subject. Thearrangement of the multiple DR detectors in this example, i.e., threedetectors, to the left of FIG. 15 is adequately described herein, suchas in reference to FIG. 12A, and is not repeated. The x-ray source 501may be configured to be translatable in a vertical direction in relationto the three detector array such that each firing of the x-ray source501 at the positions a, b, c, emits an x-ray beam 16 that exposes all ofthe multiple detectors simultaneously. Although only three exemplarypositions of the x-ray source 501 are shown, the source 501 may bepositioned and fired from any number of positions, such as fifteen orthirty positions. The x-ray source 501 may be attached to a verticalstructure, such as a vertical rail (not shown), that is used totranslate the x-ray source linearly while adjusting an aim of the x-raybeam 16 toward the array of multiple detectors. In one embodiment, thex-ray source 501 may be movably attached to an arc shaped rail (notshown) having a curvature that points the x-ray beam 16 toward thedetectors as the x-ray source moves along the arc shaped rail. In theembodiment of FIG. 15, preparatory flash images, as described herein,may be captured by each of the detectors at each of the differentpositions of the x-ray source 501. The prepatory flash images may berequired due to the varying overlap attenuation distances caused by thetop and bottom detectors overlapping the middle detector as the x-raysource is translated. The varying overlap attenuations may be compared,in certain respects, to a varying x-ray shadow projected by the bottomedge of the top DR detector onto the middle DR detector and by the topedge of the bottom detector onto the middle detector. Hence, an overlapgain correction that may be applied to the middle detector will vary foreach position of the x-ray source. Such overlap gain correction imagesmay be captured by the middle DR detector at each position of the x-raysource 501 during a preparatory stage when the x-ray source 501 may beflashed at each position that will be used for an actual subjecttomosynthesis image exposure. The overlap gain correction images canthen be stored and later used to adjust (gain correct) the correspondingsubject radiographic image. Alignment and stitching procedures forradiographic images captured using the embodiment of FIG. 15 may beimplemented using any of the methods as disclosed herein.

FIG. 16 is an exemplary flow chart that illustrates methods of operatinga radiographic imaging system 10 as disclosed herein which include twoor more DR detectors used to capture long length radiographic images ofa subject. With reference to FIG. 16, a multi-detector imaging systemmay be initialized, at step 1601, by installing DR detectors into animaging arrangement, such as by attaching or inserting two or moredetectors into a wall stand, bucky, a single housing or imagingassembly, or the transport apparatus 1251, for example, as describedherein. A calibration procedure may then be performed that includesflashing the detectors using an x-ray source to capture calibration orcorrection images as well as registration or geometric alignmentinformation. A forward positioned detector, which is not overlapped andreceives full x-ray exposure, may use the flash step to capture andstore a gain correction image to be used later during a subject imagefinalization process.

A detector positioned rearward, which is overlapped by a forwardpositioned detector, may use the flash step to capture an overlap gaincorrection image to be used for overlap gain adjustment, orcompensation, for those imaging pixels in the overlapped detector thatreceive x-rays attenuated by structures within the forward positioneddetector, and thus undergo a gain loss. Such overlapping structures mayinclude one or more of a housing, such as a carbon fiber housing whichis considered to be generally radiolucent but which may nonethelessattenuate an x-ray to some extent, electronic components, an edge of thephotosensor array, a scintillator layer whose thickness may vary, aglass layer, and other components. Any one or more of these attenuatingcomponents may extend beyond an edge of the photosensor array of theforward positioned detector. In this manner, by flashing the detectors,registration and overlap gain correction images may be obtained andstored for the multi-detector arrangement. The amount of x-ray energyreceived in the rearward detector photosensors may vary over some unitdistance in any direction in the rows and columns of photosensor imagingpixels. Thus, the overlap gain image is advantageous in mapping theenergy attenuation pattern precisely as detected by the rearwardpositioned detector. The attenuation magnitude may be determined bycomparing an x-ray intensity that is expected in a fully exposedphotosensor (as determined by, e.g., calibration exposures) with theattenuated intensity, and using that difference to thereby adjust thecorresponding imaging pixel in a captured image during gain correction.In addition, positions of any markers as described herein may beobtained and recorded. Because the positions of the detectors and/or thex-ray source may vary between successive imaging sessions, the flashstep may be performed just before each actual exposure of a subject toinsure proper registration and gain correction.

At step 1602, it may be necessary to identify if any of the multipledetectors to be used for subject radiographic imaging are withoutinternal electronic storage. In such an embodiment, it may be necessaryfor the host system to record which detector does not contain storagefor image data and to be prepared to receive read out image data fromsuch a detector immediately after exposure begins. Such a detector maybe electrically connected to the host system by wire or cable and so thecaptured image data may be transferred thereby. In one embodimentdescribed herein with respect to FIG. 12C, the middle-positioneddetector 1202 may be permanently attached to, for example, a wall standas part of a legacy imaging system, may not include internal storage forimages, and may electronically communicate with a host processing systemwirelessly or by cable. In one embodiment, the middle-positioneddetector 1202 may be a CR detector that is manually removed and carriedto a reader used to decode a phosphor plate. Digital wirelessradiographic detectors 1201, 1203, may be attached to a transportapparatus 1251, as described herein, as a retrofit to the existing wallstand detector 1202 to enable long length imaging. In this embodiment,the digital wireless detectors 1201, 1203, may include on-boardprocessing and/or electronic memory for processing and storing capturedradiographic images, as described herein with reference to FIG. 1, whichmay then be transferred out at a later time. Thus, the subject imagedata captured by detector 1202 will have to be read out first, beforeretrieving image data from detectors that have electronic storage forcaptured image data, in this embodiment. Information regarding whichdetector does not contain internal storage is determined before x-rayexposure begins as part of initializing the imaging system.

At step 1603, the imaging system transmits activation signals to themultiple detectors to place the detectors into a ready state for imagecapture. A host processor, for example, then waits to receive a readysignal from all the detectors that are equipped to transmit a readysignal and which will be used for image capture. After all the expectedready acknowledgments are received, the x-ray source is triggered forexposure. The multiple detectors each capture a portion of aradiographic image of the subject in response to a single x-rayexposure. At step 1604, a detector without digital memory for storingthe captured image, if any, reads out and transmits the image data, suchas via a connected cable or wirelessly, to the host processing systemand the captured image is then stored and processed in the host system.Simultaneously, indicated at step 1605, detectors having on-boardelectronic memory for storing the captured radiographic image may readout and store internally the captured image data until instructed totransmit, or transfer, the image data, by cable or wirelessly, to thehost system. At step 1606, such detectors may also initiate on-boardprogramming for defect concealment or other error corrections, offsetcorrection, gain correction, and other image processing functions togenerate final viewable image data, or such image processing functionsmay be performed at the host system. Stitching together the multipleimages captured by the detectors to form a long length image may beperformed at the host system which has received and stored all theassociated captured radiographic images. In particular, the host systemmay utilize an overlap gain map to compensate individual pixel's imagedata captured in overlapped pixels as described herein. The host systemmay also use row identifiers providing precise row overlap positions ofthe images captured by overlapping detectors for proper geometricalignment when digitally stitching together the captured images in orderto form the long length image.

FIGS. 17A-B are each schematic front and side views of first and seconddetectors 1701, 1702, arranged in an overlapping fashion within a singlehousing 1703. As shown, the upper detector 1701 is positioned in frontof the lower detector 1702, in relation to an x-ray source (not shown).The side of the housing 1703 facing the x-ray source may include adouble sized grid 1704 attached thereto. As shown in FIG. 17B, anoptional third detector 1707 may be arranged above the pair of detectors1701, 1702, to increase a size of a long length DR image of a subjectcaptured simultaneously in all three of the arranged DR detectors 1701,1702, 1707. As described herein above, a detector, such as detector1701, that is positioned forward (in front of) overlapped detectors,such as detectors 1702 and/or 1707, may include radiolucent material toform the overlapping edge or edges thereof. The side of the threedetector configuration housing (front) facing the x-ray source mayinclude a triple sized grid 1705 attached thereto.

FIG. 18 is a functional block diagram of an imaging assembly comprisingtwo DR detectors 1701, 1702, as described herein, enclosed within ahousing 1703. Each of the DR detectors 1701, 1702, is electricallyconnected to a separate power regulator 1801, which, in turn, areelectrically connected to a power management hub 1803. The powerregulator 1801 controls powering-up of two or three detectors in theimaging assembly and their data processors, controls refresh operationsand data processing sequencing among the two or three detectors, andmaintains full operation of the imaging assembly. The power managementhub 1803 is electrically connected to a power source such as an on-boardbattery, or an external power supply provided via hub 1807 which mayinclude an external battery or a main medical facility power source. Thepower management hub 1803 manages a single energy input, either powersupplied from a battery or from an external power facility supply viahub 1807, and manages distribution of power to two or three detectorsfor normal operations or for charging a battery in the imaging assembly.The power management hub 1803 also controls a single external connector2205 (FIGS. 22A, B, D) to manage wired communication among two or threedetectors with an external network console 1805. The power source usedprovides sufficient power for all operations performed by the DRdetectors 1701, 1702, and the imaging assembly. Each of the DR detectors1701, 1702, include a wireless interface having a transmitter/receiverfor wireless communications with imaging console 1805, via a wirelessaccess point (WAP) connected to the imaging console 1805. Each of the DRdetectors 1701, 1702, may be electrically connected to the imagingconsole 1805 via a cable that carries power and data through a hub 1807using a network protocol such as an Ethernet protocol. One feature ofthe imaging assembly makes use of a single external connector 2205(FIGS. 22A, B, D) providing an electrical connection to external sourcesfor power transmission and Ethernet data communication. The imagingconsole 1805 includes a processing system for controlling operation ofthe imaging assembly, synchronization of image captures by the detectors1701, 1702, x-ray source firing, image transmission and imageprocessing. A third detector having an electrical connector 2202 (FIG.23D) thereon may be electrically connected to the imaging assembly via amating electrical connector 2201 (FIGS. 22A, D) on the housing 1703.This electrical connection merges the third detector 1707 into theimaging assembly for purposes of simultaneous LLI capture and systemcommunication and sequencing, whereby the third detector 1707 shares inreceiving power distribution and wired and wireless data communicationwith the console 1805.

FIGS. 19-20 are side and front view schematic diagrams, respectively,showing the double imaging assembly 1910 of two detectors 1701, 1702,secured within extendable housing 1703, as described herein withrelation to FIG. 17A. With reference to FIGS. 19 and 20, a double sizedgrid 1704 may be attached to a front side of the housing 1703. Thedouble imaging assembly 1910 may be attached to a movable imaging cart1900 comprising a base section 1903 having wheels 1901 for rolling theimaging cart 1900 over a surface such as a floor. A vertical column 1907is attached to the base 1903. A horizontal arm 1909 is attached to thecolumn 1907 and to the double imaging assembly 1910. The horizontal arm1909 may be extendable and retractable in a horizontal direction awayfrom and toward the vertical column 1907, such as being fabricated in atelescoping configuration. The horizontal arm may be attached to thedouble imaging assembly 1910 via a joint that is rotatable in at leasttwo dimensions, and preferably in three dimensions as described hereinbelow.

FIGS. 21A-B are side and front view schematic diagrams, respectively,showing the triple imaging assembly 1920 of three detectors 1701, 1702,1707, secured within extendable housing 1703 extended to enclose anadditional third detector 1707, as described herein with relation toFIG. 17B. With reference to FIGS. 21A-B, a triple sized grid 1705 isattached to a front side of the extended housing 1703. The tripleimaging assembly 1920 may be attached to a movable imaging cart 1900comprising a base section 1903 having wheels 1901 for rolling theimaging cart 1900 over a surface such as a floor. A vertical column 1907is attached to the base 1903. A horizontal arm 1909 is attached to thecolumn 1907 and to the triple imaging assembly 1920. The horizontal arm1909 may be extendable and retractable in a horizontal direction awayfrom and toward the vertical column 1907, such as being fabricated in atelescoping configuration. The horizontal arm may be attached to thetriple imaging assembly 1920 via a joint that is rotatable in at leasttwo dimensions, and preferably rotatable in three dimensions asdescribed herein below.

FIGS. 22A-B are perspective views of the housing 1703 enclosing twodetectors 1701, 1702, therewithin, and FIGS. 22C-D are front and rearviews thereof, respectively. A rear side of the housing 1703 is facingupward in the perspective views of FIGS. 22A-B. The housing 1703 isconfigured to be attached to a third detector 1707. The housing 1703comprises a lip 2203 made from a radiolucent low attenuation materialextending from the main body of the housing 1703 to assist in a blindinsertion of a third detector 1707 as described herein. The radiolucentlow attenuation material of the lip 2203 may overlap a third detector ina three detector embodiment (FIGS. 23A-D). One edge of the thirddetector 1707 rests against the surface 2207 of the housing 1703 whenthe triple imaging assembly 1920 is assembled. An electrical connector2201 in the housing 1703 is configured to electrically engage a matingconnector of the third detector 1707 when assembled, which electricalengagement allows power and wired data transmission and synchronizationas explained above with reference to FIG. 18. A single externalconnector 2205 is electrically coupled to two or three detectors andenables power and wired data transmission (Ethernet) between two orthree detectors and an external processing system (console) when theexternal processing system is electrically coupled to connector 2205.

FIGS. 23A-B are perspective views of the housing 1703 enclosing twodetectors 1701, 1702, therewithin, electrically attached to a thirddetector 1707, and FIGS. 23C-D are front and rear views thereof,respectively. A rear side of the housing 1703 and detector 1707 isfacing upward in the perspective views of FIGS. 23A-B. The thirddetector 1707 abuts the radiolucent lip 2203 extending from housing 1703as well as a surface 2207 of the housing 1703. One edge of the thirddetector 1707 rests against the surface 2207 of the housing 1703 asshown in FIGS. 23A-D when the triple imaging assembly 1920 is assembledas described herein. An electrical connector 2201 in the housing 1703 isconfigured to electrically engage a mating connector 2202 of the thirddetector 1707 when assembled, which electrical engagement allows powerand data transmission as well as synchronization among the threedetectors 1701, 1702, 1707, as explained above.

FIGS. 24A-E are perspective views of the imaging cart 1900 having anassembled double imaging assembly 1910 attached thereto as describedabove in relation to FIGS. 19-20. The extendable housing 1703 having anextendable top portion 2401 encloses two detectors 1701, 1702, andincludes an attached double sized grid 1704 on the front of the housing1703. As described above in relation to FIGS. 19-20, the double imagingassembly 1910 may be attached to a movable imaging cart 1900 comprisinga base section 1903 having wheels 1901 for rolling the imaging cart 1900over a surface such as a floor. A vertical column 1907 is attached tothe base 1903. An extendable horizontal arm 1909 is movably attached tothe column 1907 to allow raising and lowering of the horizontal arm,relative to the vertical column 1907, and thereby raising and loweringthe double imaging assembly 1910 together therewith. The horizontal arm1909 may be extendable and retractable in a horizontal direction awayfrom and toward the vertical column 1907, such as being fabricated in atelescoping configuration. The horizontal arm 1909 may be attached tothe double imaging assembly 1910 via a joint 2407 that is rotatable inat least two dimensions, and preferably in three dimensions as describedherein below. The imaging cart 1900 may be outfitted with a bin 2405 forstoring a detector 2404 therein, which bin may also be configured withan electrical connector to engage an electrical connector of thedetector 2404 for charging the detector 2404. A handle 2403 attached tothe vertical column 1907 near the top thereof, allows manual controlover rolling movement of the imaging cart 1900 using the wheels 1901. Apedal 2406 may be provided for locking the wheels 1901 to prevent freerolling of the wheels 1901.

FIG. 24C illustrates movement of the horizontal arm 1909 downward alonga track 2409 in the vertical column 1907, as compared with FIG. 24A, anda rotation of the double imaging assembly 1910 about a first horizontalaxis 2411 intersecting, and perpendicular to, the vertical arm 1907.FIG. 24D illustrates movement (rotation) of the double imaging assembly1910 about a second horizontal axis 2413 that is generally perpendicularto the first horizontal axis 2411 to enable imaging of a supine patientby positioning the double imaging assembly 1910 beneath the patient. Thepositioning of imaging assembly 1910 as described herein above andillustrated in FIGS. 24A-D enables erect, supine, and cross-tableimaging of a patient in an x-ray exam room or in bedside locations suchas a patient room, operating room, emergency room or intensive careunit. FIG. 24D also illustrates movement of the double imaging assembly1910 horizontally (arrow) by extending the telescoping horizontal arm1909 away from the vertical column 1907. In one embodiment, the verticalcolumn 1907 may also be fabricated in a telescoping configuration toraise and lower the double imaging assembly 1910.

FIG. 24E illustrates movement of the double imaging assembly 1910 abouta third axis 2413 that is vertically oriented and is perpendicular toboth horizontal axes 2411 and 2413. The orientation of the doubleimaging assembly 1910 as illustrated in FIG. 24E allows positioning thedouble imaging assembly 1910 closer to an obstacle, such as parallel toa wall in an imaging room, because the width dimension W of the imagingcart 1900 is less than the perpendicular length dimension thereof. FIG.24F illustrates lowering of the double imaging assembly 1910 by loweringthe horizontal arm 1909 to enable capturing a long length lower body(e.g., legs) DR image of a patient P standing on a short pedestal 2415.The horizontal arm 1909 may also be moved vertically upward alongvertical column 1907 to enable capturing a long length upper body (e.g.,spine) DR image of a patient P. In one embodiment of the imagingassembly 1910, the imaging area of the two detectors may be about17″×33″ and the imaging area of the three detector embodiment may beabout 17″×49″, although these dimensions may vary based at least onsizes of the individual detectors and on the imaging assembly overlapdimensions.

FIGS. 25A-B are perspective views illustrating conversion of the doubleimaging assembly 1910 into the triple imaging assembly 1920. Asillustrated in FIG. 25A, the extendible top 2401 may be extended toallow insertion of detector 1707 under a lip 2402 of the extendible top2401. The third detector 1707 is positioned against a top edge of thehousing 1703 (not visible) behind double sized grid 1704 of the doubleimaging assembly 1910, as explained above in relation to FIGS. 23A-D.This electro-mechanical engagement of the third detector 1707 to thetwo-detector housing 1703 is also described above in relation to FIGS.21A-B and FIGS. 22A-D. After the third detector 1707 is inserted andpositioned against the top of the housing 1703 within double imagingassembly 1910, a lip 2402 of the extendible top 2401 may be positionedagainst the top edge of third detector 1707 to secure it in positionparallel to the two detectors 1701, 1702 of the double imaging assembly1910. As illustrated in the perspective view of FIG. 25B, a triple sizedgrid 1705 is used to replace the double sized grid 1704, therebycompleting the assembly of triple imaging assembly 1920, which ismaneuverable in three dimensions similar to the movement of the doubleimaging assembly 1910 described above in relation to FIGS. 24A-F.

FIGS. 26A-B illustrate features of the movable imaging cart 1900 wherebythe double imaging assembly 1910 comprises a radiolucent front surface2601 and the double sized grid 1704, which double sized grid 1704 may beattached to the double imaging assembly 1910 in front of the radiolucentfront surface 2601. A soft cover 2603 may also be positioned over thedouble sized grid 1704 to protect the double imaging assembly 1910 whilebeing transported using the movable imaging cart 1900. FIG. 26Billustrates a bin attached to the horizontal arm 1909 to hold adetector, battery, or other device 2603. An LED monitor 2605 may beplaced on a top of the vertical column 1907 to display various status ofthe imaging cart 1900.

FIGS. 27A-B illustrate features of the imaging cart 1900 to enableprecise placement of the imaging assembly 1910, 1920, duringradiographic image capture. FIG. 27A illustrates a centerline marking2701 aligned on fixed and telescoping portions of the horizontal arm1909 which may be used together with illuminated collimator crosshairs2705 emitted by an x-ray tube head and projected onto a patient P beingradiographically imaged. As shown in FIG. 27B, the centerline 2701 onthe horizontal arm 1909 may be visually aligned by a technician with acrosshair 2705 projected onto a collimator illumination region 2703. Toalign a center 2707 of the projected crosshairs 2705 with a center ofthe imaging assembly 1910, 1920, an extendable coiled tape measure 2702may be provided near a top of the vertical column 1907 to measure andrecord a distance to a center of the imaging assembly 1910, 1920. Thetape measure may then be manually extended over the patient P until therecorded distance on the tape measure 2702 aligns with a center 2707 ofthe illuminated collimator cross hairs 2705.

FIGS. 28A-B illustrate use of a bracket 2801 secured to a wall forhanging and storing the double and/or triple sized grids 1704, 1705. Asshown in FIG. 28B, the movable imaging cart 1900 may be wheeled up tothe hanging grid to position the imaging assembly 1910 or 1920 near to,or in contact with, the hanging grid 1704, 1705, in order to more easilyplace one of the double and/or triple sized grids 1704, 1705 onto afront of the imaging assembly 1910, 1920, respectively. Similarly, themovable imaging cart 1900 may be wheeled up to the bracket 2801 toposition the imaging assembly 1910 or 1920 near the bracket 2801 inorder to more easily remove one of the double and/or triple sized grids1704, 1705, from the front of the imaging assembly 1910, 1920,respectively, to hang it on the bracket 2801.

FIGS. 29A-B are perspective views of embodiments of immobile imagingsystems 2900, 2910, respectively, whereby imaging assemblies 1910, 1920(embodiment using only imaging assembly 1910 is illustrated in FIGS.29A-B) may be movably attached to immobile structures. FIG. 29Aillustrates a floor mounted embodiment 2900 whereby a vertical column2901 may be secured by its base 2903 to a floor in an imaging facility.As described herein with respect to vertical column 1907 of the movablecart 1900, the floor mounted column 2901 includes a vertical track 2905whereby the imaging assembly 1910, 1920, attached thereto, may be movedvertically along the track 2905 of the vertical column 2901 to a desiredheight for imaging a patient positioned proximate the imaging assembly1910, 1920.

FIG. 29B illustrates a wall mounted embodiment having a vertical slottedpanel 2907 that may be secured to a wall in an imaging facility. Thewall mounted panel 2907 includes a number of slots 2909 in the verticalpanel 2907 whereby the imaging assembly 1910, 1920, may be movedvertically along the panel 2907 to a desired height for imaging apatient positioned proximate the imaging assembly 1910, 1920. The slots2909 may serve to engage a detent mechanism of the imaging assembly1910, 1920. The imaging assembly 1910, 1920 may include a detentmechanism attached to a rear side thereof to selectively engage one ofthe slots 2909 of the vertical panel 2905 at a desired height to securethe imaging assembly 1910, 1920, at the desired height. In theembodiments described herein: the movable cart 1900, the floor mountedembodiment 2900, and the wall mounted embodiment 2910, the imaging panelassembly 1910, 1920, may be lowered such that a bottom edge of theimaging panel assembly 1910, 1920, approaches a floor to within an inchthereof, or may be lowered to make contact with the floor.

FIG. 30 illustrates a radiolucent patient table 3001 that may be usedtogether with the movable imaging cart 1900 described herein. Thepatient table 3001 comprises an upper surface 3003 for supporting asupine patient P. The patient table 3001 further comprises supports 3005at opposite edges of the table 3001 to provide a height H beneath theupper surface 3003 sufficient for positioning an imaging assembly 1910,1920 underneath the support surface 3003. In other embodiments, thesupports may be formed as table legs, wheels for rolling the patienttable across a floor, beams, or other support shapes. The patient table3001 may be positioned on existing imaging equipment in an x-ray examroom such as an existing x-ray table 3007, or the patient table 3001 maybe positioned on a floor of the x-ray exam room in order to maximize aSID as between an x-ray tube and an imaging assembly 1910, 1920,positioned underneath the patient table 3001. In some circumstances, thex-ray tube in an exam room may not be maneuverable to a sufficientheight for maximum LLI exposure, therefore, lowering a supine patient asclose as possible to a floor using the patient table 3001 may beadvantageous. In either position, i.e., on an existing x-ray table or ona floor, the movable imaging cart 1900 is capable of adjusting a heightof the imaging assembly 1910, 1920, by vertically moving the horizontalarm 1909 to an appropriate height and then wheeling the mobile imagingsystem 1900 or extending the telescoping horizontal arm 1909 to positionthe imaging assembly underneath the imaging table 3001.

As will be appreciated by one skilled in the art, aspects of the presentinvention may be embodied as a system, an apparatus, and a method, forcapturing long length images of a subject using multiple DR detectors.This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they have structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal language of the claims.

What is claimed is:
 1. A digital radiographic detector systemcomprising: a plurality of DR detectors each comprising a radiographicimaging array; a base having a plurality of wheels for wheeling thesystem over a surface; a vertical column attached to the base; an armhaving a distal end and a proximal end opposite the distal end, theproximal end of the arm attached to the vertical column, the armconfigured to move vertically along the vertical column; and a housingattached to a distal end of the arm, the housing comprising a majorsurface made from a radiolucent material; wherein the housing enclosesand supports therewithin the plurality of DR detectors, and wherein theradiographic imaging array of the plurality of DR detectors each facesthe housing major surface made from the radiolucent material.
 2. Thesystem of claim 1, further comprising: a rotatable joint attached to thehousing and to the arm to rotatably attach the housing to the arm, therotatable joint configured to enable variable positioning of the housinginto at least two positions, wherein a first position of the housingincludes the major housing surface positioned in a vertical plane facingaway from the column, and wherein a second position includes the majorhousing surface lying in a horizontal plane facing upward.
 3. The systemof claim 1, wherein the housing supports therewithin the plurality of DRdetectors each in a plane parallel to one another, wherein the housingis configured to receive an additional DR detector and to secure theadditional DR detector within the housing in a plane parallel to theplanes of the plurality of DR detectors.
 4. The system of claim 1,further comprising a wall hanger for hanging a grid thereon, the wallhanger configured to facilitate securing the hanging grid onto the DRimaging system when the DR imaging system is wheeled close to the wallhanger such that the housing contacts the hanging grid.
 5. The system ofclaim 1, wherein at least one of the plurality of detectors comprises afirst communication connector configured to receive and engage acorresponding second communication connector on an additional detector,and wherein the additional DR detector is configured to communicatedetector identification information through the communicatively engagedfirst and second connectors.
 6. The system of claim 5, wherein theplurality of detectors and the additional detector each compriseelectronic wireless communication circuits, and wherein the additionalDR detector is configured to communicate detector identificationinformation wirelessly or through the communicatively engaged first andsecond connectors.
 7. The system of claim 6, wherein the plurality ofdetectors and the additional detector are configured to communicate withonly one controller external to the DR detector system, and wherein theone controller is configured to control power distribution to thedetectors within the housing and to control data connections between thecontroller and the detectors within the housing.
 8. The system of claim1, further comprising: a rotatable joint attached to the housing and tothe arm to rotatably attach the housing to the arm, the rotatable jointconfigured to enable variable positioning of the housing into at leasttwo positions, wherein a first position of the housing includes themajor housing surface positioned in a vertical plane facing in ahorizontal first direction, and wherein a second position includes themajor housing surface revolved about an axis parallel to the columnfacing in a horizontal second direction perpendicular to the firstdirection.
 9. The system of claim 1, further including a single externalconnector on the housing that includes channels for transmitting powerto the detectors, data to and from the detectors, and controlinstructions to and from the plurality of DR detectors.
 10. A digitalradiographic detector system comprising: a plurality of DR detectorseach comprising a radiographic imaging array; a base affixed to a floor;a vertical column attached to the base; a movable support attached tothe vertical column, the support configured to move vertically along thevertical column; and a housing attached to the vertical support, thehousing comprising a major surface made from a radiolucent material,wherein the housing encloses and supports therewithin the plurality ofDR detectors, and wherein the radiographic imaging array of theplurality of DR detectors each faces the major housing surface.
 11. Thesystem of claim 10, further comprising: a rotatable joint attached tothe housing and to the movable support to rotatably attach the housingto the support, the rotatable joint configured to enable variablepositioning of the housing into at least two positions, wherein a firstposition of the housing includes the major housing surface positioned ina vertical plane facing away from the column, and wherein a secondposition includes the major housing surface rotated in the verticalplane.
 12. The system of claim 10, wherein the housing supportstherewithin the plurality of DR detectors each in a plane parallel toone another, wherein the housing is configured to receive an additionalDR detector and to secure the additional DR detector within the housingin a plane parallel to the planes of the plurality of DR detectors. 13.The system of claim 10, wherein the housing is configured to securethereto a grid in a position parallel to the major surface of thehousing.
 14. The system of claim 10, wherein at least one of theplurality of detectors comprises a first communication connectorconfigured to receive and engage a corresponding second communicationconnector on an additional DR detector, and wherein the additional DRdetector is configured to communicate detector identificationinformation through the communicatively engaged first and secondconnectors.
 15. The system of claim 10, wherein the plurality ofdetectors and the additional detector each comprise electronic wirelesscommunication circuits, and wherein the additional DR detector isconfigured to communicate detector identification information wirelesslyor through the communicatively engaged first and second connectors. 16.The system of claim 15, wherein the plurality of detectors and theadditional detector are configured to communicate with only onecontroller external to the DR detector system, and wherein the onecontroller is configured to control power distribution to the detectorswithin the housing and to control data connections between thecontroller and the detectors within the housing.
 17. The system of claim10, further including a single external connector on the housing thatincludes channels for transmitting power to the detectors, data to andfrom the detectors, and control instructions to and from the pluralityof DR detectors.
 18. A digital radiographic detector system comprising:a plurality of DR detectors each comprising a radiographic imagingarray; a vertical hanger having a plurality of first detent portionsarranged vertically in relation to one another, the vertical hangerattached to a vertical surface; a manually movable support attached tothe vertical hanger, the support configured to move vertically along thevertical hanger and comprising a second detent portion to lockablyengage the movable support to any one of the first detent portions; anda housing attached to the movable support, the housing comprising amajor surface made from a radiolucent material, which major surfacefaces away from the vertical surface, wherein the housing encloses andsupports therewithin the plurality of DR detectors, and wherein theradiographic imaging array of the plurality of DR detectors each facesthe major housing surface.
 19. The system of claim 18, furthercomprising: a rotatable joint attached to the housing and to the movablesupport, the rotatable joint configured to enable variable positioningof the housing into at least two positions, wherein a first position ofthe housing includes the major housing surface positioned in a verticalplane facing away from the vertical surface, and wherein a secondposition includes the major housing surface rotated in the verticalplane.
 20. The system of claim 19, wherein the housing supportstherewithin the plurality of DR detectors each in a plane parallel toone another, wherein the housing is configured to receive an additionalDR detector and to secure the additional DR detector within the housingin a plane parallel to the planes of the plurality of DR detectors.